1. Field of the Invention
The present invention relates to a method for producing a conductive pattern and a method for producing a greensheet lamination body including the same, both of which are used for an electronic component such as a lamination chip inductor.
2. Description of the Related Art
Recently, electronic components have been significantly reduced in size, and thus lamination chip inductors which are smaller and have a higher impedance have been demanded. Production of such a lamination chip inductor requires conductive patterns formed therein to be finer and thinner and to have a higher density.
Development of compact electronic devices having a high level of performance such as cellular phones requires a chip-type LCR module having various functions. Production of such an LCR module also requires efficient formation of fine conductive patterns having a sufficient density.
Such conductive patterns are generally produced by conventional printing. In order to form finer patterns, various methods have been attempted including offset printing, enlargement of the aperture ratio of the screen in screen printing, use of a conductive powder having a smaller diameter, and improvement in the vehicle used for preparing the powder. By such methods, the width of the conductive patterns cannot be reduced to less than 50 to 80 .mu.m for practical use. Further, the conductive patterns tend to have less thickness as the width is reduced, which increases the resistance thereof.
As a solution to the above-described problems, Japanese Laid-Open .Patent Publication No. 4-314876 discloses a method for forming a conductive pattern using transfer. In this method, a releasable thin metal layer formed by evaporation is treated with wet plating to obtain a desirable metal layer, and an extra area of the resultant metal layer is removed by etching as necessary to obtain a desired pattern. The resultant pattern is transferred onto a support layer. By such a method, a relatively thin metal conductive pattern (having a thickness of, for example, 10 .mu.m or less) can be formed to be used as an internal electrode for a lamination ceramic capacitor or the like.
However, production of a fine conductive pattern becomes more difficult as the thickness of the metal layer increases (for example, to more than 10 .mu.m) by this method.
Further, since the desired pattern is obtained under a mask layer used for etching, the mask layer needs to be removed before the transfer. When the mask layer is removed, the conductive pattern may also be undesirably removed. Such a phenomenon becomes more prevalent as the thickness of the metal layer increases. The reason is that, as the thickness of the metal layer increases, etching takes a longer period of time and thus the thin metal film is exposed to the etchant at a higher degree.
Moreover, the above-described method is not very efficient because a mask layer for etching needs to be formed on the metal layer for formation of each conductive pattern.